Compliance details last reviewed on 4 October 2026. Tax rules change often. This is general information, not tax or legal advice, so confirm specifics with your chartered accountant.
Most e-invoicing trouble comes from the gap between the invoice your team finalises and the invoice the portal accepts. A wrong GSTIN, a number reused after a correction, an invoice sitting unreported for five weeks: each is small, and each lands when a customer is waiting.
This guide explains GST e-invoicing in plain terms: what it is, who has to do it, how the IRN is generated, the 30-day reporting limit, how an e-invoice connects to an e-way bill, the errors that come up most often, and a checklist to run before an invoice goes out. It is a companion to the wider B2B accounting workflows guide.
What GST e-invoicing is
E-invoicing is not a new kind of invoice and not a new way to create one. You still raise the invoice in your own books or ERP. The change is that, for covered taxpayers, the invoice data must be reported to an Invoice Registration Portal (IRP).
The portal validates it and returns an Invoice Reference Number (IRN) together with a signed version of the invoice. A signed QR code is also widely described as part of that output, though you should confirm the exact format on the portal.
The invoice therefore has an official identity before the customer sees it, and mismatches between your books and the portal tend to surface later in returns. On the buying side, the same invoices show up in your GSTR-2B reconciliation.
Who must issue e-invoices
Generally, e-invoicing applies to registered taxpayers whose aggregate turnover exceeded Rs 5 crore in any financial year from 2017-18 onward. This comes from Notification 10/2023-Central Tax dated 10 May 2023, in force from 1 August 2023.
Treat that as the starting point and confirm the current position with your CA or on the portal, because the notification also carries exemptions and conditions that depend on your type of business.
The test looks backwards: it uses turnover in any year since 2017-18, not only last year, so a business can fall under e-invoicing even if current turnover has dipped. Name one person who checks applicability each April and records the conclusion.
How IRN generation works
The sequence is short:
- Your system prepares the invoice data and your team checks it.
- The data is sent to the IRP, directly or through a connected system.
- The IRP validates it, generates the IRN and signs the e-invoice.
- You store the IRN against the invoice and only then send it to the customer.
The order matters. The invoice should not leave your business until step 3 is complete and the IRN is stored.
What an IRN is built from
According to the official IRP FAQ, the IRN is 64 characters long and is generated using SHA-256 from a combination of four values: the supplier GSTIN, the document type, the document number and the financial year of the invoice. Invoices, credit notes and debit notes each count as a document type.
Because the document number is an input, numbering discipline matters. Keep one series per document type and financial year, and never reuse a number.
The 30-day reporting limit
A GSTN advisory dated 5 November 2024 set a time limit. From 1 April 2025, taxpayers with an aggregate annual turnover (AATO) of Rs 10 crore and above cannot report e-invoices older than 30 days from the date of reporting on the IRP.
The limit applies to all IRN document types: invoices, credit notes and debit notes. As of the advisory, no such limit is stated for taxpayers below that turnover, so check the portal for the current position before you assume it stays that way.
The limit changes how teams should work:
- Report on the day of finalising. Treat "final" and "reported" as one step.
- Watch the backlog. Keep a daily list of final invoices with no IRN, with a name against anything approaching 20 days.
- Late credit notes count too. A credit note raised weeks later is its own document and needs reporting within the window.
E-way bills and e-invoices
An e-way bill is a separate document for the movement of goods. It is generally needed when the consignment value exceeds Rs 50,000.
For regular cargo, validity is one day for every 200 km or part of it, and an e-way bill can be cancelled within 24 hours of generation. Confirm the current limits on the e-way bill portal, since they vary by case.
The link between the two is convenience. An e-invoice that already has an IRN is widely described as usable to generate the e-way bill, so the transport details are added to data you have already validated instead of being typed again. If you can do it that way, do.
The working rule for dispatch is simple: no IRN, no e-way bill, no truck.
| Item | E-invoice | E-way bill |
|---|---|---|
| What it records | The sale and its tax details | The movement of goods |
| Who it concerns | Customer, GST systems | Transporter, officers checking goods on the road |
| Main identifier | IRN | E-way bill number |
| Typical trigger | Final B2B invoice | Consignment above Rs 50,000 in value (generally) |
| Time pressure | 30-day reporting limit (AATO Rs 10 crore and above) | Validity by distance; cancellation window of 24 hours |
Common errors in e-invoicing
These come up repeatedly in finance teams. Most are process errors, not software errors.
- Reporting late. The invoice was finalised, but nobody triggered the IRN. Fix it with a daily list of final invoices that have no IRN.
- Editing after the IRN exists. The amount or customer is changed in the books while the portal still holds the original. The books and the portal then disagree. Once an IRN exists, correct through a credit or debit note, not an edit.
- Wrong GSTIN or place of supply. The data is entered or imported with a typo or an old customer record. Check these before generation, not after a rejection.
- Duplicate or reused document numbers. A cancelled number is issued again, or two branches share a series. Keep one series per document type and financial year.
- Sending the invoice first. The PDF goes out before the IRN is stored, and the customer holds a document the portal has not seen. Make "IRN stored" a precondition for sending.
- Dispatching before the e-way bill. The goods move on an invoice that has an IRN but no e-way bill. Make dispatch wait for both.
- Forgetting credit and debit notes. They are covered by the same reporting limit.
A pre-send checklist
Run this before any invoice leaves:
- Customer GSTIN, place of supply and HSN are checked against the master record.
- The invoice number is the next in the series for its document type and financial year.
- The invoice is final, with no pending edits.
- The IRN has been generated and stored against the invoice.
- For goods moving, the e-way bill exists and matches the invoice.
- The invoice is within the reporting window if the 30-day limit applies to you.
- Any correction made after the IRN is a credit or debit note, not an edit.
Where OpsGrids Finance fits
OpsGrids Finance covers invoices, payments and allocations against them, GST registration, returns and a diff against your books, and TDS withholding, on a full ledger. The e-invoicing (IRN), e-way bill and IMS workflows are e-invoice-ready but run against a simulated government portal today; until the live connection ships, use the official portals or your GST Suvidha Provider.
Invoices are append-only: a correction is a new row, which matches the credit-note discipline above. Events such as an invoice being finalised can be sent to people by email, or on WhatsApp once your WhatsApp Business account is connected through Meta, through notification rules.
No software guarantees compliance. Your data, the portal's availability and your CA's judgement still decide the outcome. If you are also tightening how you pay suppliers, the guides on TDS under the Income-tax Act, 2025 and procure-to-pay for MSME rules cover the other half.
FAQ
What is an IRN and how long is it? The Invoice Reference Number is 64 characters long. The Invoice Registration Portal generates it using SHA-256 from the supplier GSTIN, document type, document number and the financial year of the invoice.
Does the 30-day limit apply to my business? Per the GSTN advisory of 5 November 2024, it applies from 1 April 2025 to taxpayers with AATO of Rs 10 crore and above. No limit is stated for lower turnover as of that advisory. Confirm the current position with your CA or on the portal.
Do I need an e-way bill if I have an IRN? They are separate documents. An e-way bill is generally needed when the consignment value exceeds Rs 50,000, and an IRN-holding e-invoice is widely described as usable to generate it. Confirm current rules on the e-way bill portal.
Can I cancel or fix an e-invoice after the IRN is generated? Treat the IRN as the invoice's identity. Avoid editing the invoice in your books. For corrections, use a credit or debit note, and ask your CA how the portal's cancellation options apply to your case.
Talk through your e-invoicing process
If you want to see how this flow would work with your own invoices and dispatches, Talk to our team.
Sources (checked 4 October 2026)
- GSTN advisory on the 30-day e-invoice reporting limit, 5 November 2024 (einvoice.gst.gov.in)
- Official IRP FAQ and IRN specification, Invoice Registration Portal (einvoice6.gst.gov.in)
- Notification 10/2023-Central Tax, 10 May 2023 (gstcouncil.gov.in/node/4365)
- E-way bill portal (ewaybillgst.gov.in), where the current value limits and validity should be confirmed; the figures in this article come from secondary reports